The objective of this work was to determine the viscosity of the modified starch that sell in the Panama Republic at commercial level. The modified starch was prepared at different concentrations (0.1, 0.3, 0.5, 0.8, 1.1, 2.0, and 4.0%). These samples were measured with the Brookfield DV - II viscometer at the same temperature. The results obtained, shown that, when the concentration of starch is increased the viscosity increase as well, at the same time, when increased the revolutions per minute of 12, 30 and 60 (RPM) decreased the viscosity. Note that the viscometer marked error when the concentration of the modified starch were less than 2%.